Horizontal Directional Drilling (“HDD”) continues to grow as a construction alternative to open trenching for installation of conduit and pipelines for underground utilities. One discipline of the HDD industry is the delivery of fiber optic and high speed telecommunication transmission lines to homes and businesses, which is commonly called “Fiber to the Home” (“FTTH”) or “Fiber to the Premises” (“FTTP”). With a majority of the primary fiber lines installed connecting major population areas across the United States, there is now a push to install optical fiber from local distribution hubs to each home. HDD is playing a large role in installing fiber to homes or businesses with as little disruption as possible to streets, sidewalks, driveways and landscapes. One aspect of this type of drilling is hole size. In most other HDD projects, an initial hole or “pilot hole” is made and a reamer or “hole opener” is pulled back and forth through the hole until an adequate size is achieved to allow passage of a selected size pipe or conduit. For FTTP projects the pilot hole is typically of adequate size for receiving one inch diameter conduit for passing a fiber line to an individual home or small premises. These bores are usually short and shallow and drilled with a small HDD rig, with FTTP boring contractors often making a number of these bores a day.
FTTP contractors who use rock bits to drill these short bores consider speed as being critical to profitability. Upon completing the pilot hole for an FTTP project, the end of a drilling tool string will exit the terminal end of the borehole and be pushed outward to expose a drill bit. The drill bit is then often removed and a separate device is secured to the end of the tool string to which a fiber conduit is connected for pulling back through the borehole with the tool string. Removal of the drill bit and installation of a pull back device is time consuming, and repeated removal and installation of the drill bit provides opportunity for damage to threaded connections and seals. Some HDD paddle bits have included a hole in the end of the paddle bits for attaching a shackle to connect pull back attachments for the conduit. Some offset rock bits have had a removable cutting tooth insert replaced by a tooth-like insert having an eye for attaching a shackle. However, these pull back attachment solutions result in securing pull back attachment devices to the drill string at points which are offset from a central longitudinal axis of the drill string, resulting in fiber conduit cutting into the wall of the borehole and becoming stuck during pull back.